Safety razor blade



Dec. 5, 1944.

J. MUROS SAFETY RAZOR BLADE Filed Feb. 19, 1944 JO/J e 01: Mara/.1,INVENTOR.

Patented Dec. 5, 1944 SAFETY RAZOR- BLADE Joseph Muros, Cambridge,Mass., assignor to Gillette Safety Razor Company, Boston, Mass., acorporation of Delaware Application February 19, 1944, Serial No.523,005

Claims.

This invention relates to safety razor blades and consists in animproved blade of the thin, flexible, open-end type.

Open-end razor blades, that is to say, blades having two sharpenedside-portions connected at one end only by a transverse flexible hingeportion, have the advantage that they may be presented in shavingposition by endwise movements between the blade-clamping members of thesafety razor and are thus adapted for use in safety razors wherein theblade-clamping members are permanently connected by means permittingonly a limited separation. Blades of this type may, of course, be usedlike any other blades in razors wherein the cap and guard members arenot permanently connected.

It has been appreciated for some time that in safety razors wherein theblade is transversely It should be understood that in deflecting thehinge portion of the blade it is desirable to maintain to some degree atleast the resilient characteristics of the tempered steel from which theblade is formed. Desirable results are secured,

flexed when it is clamped in shaving position, as

in the Gillette type of safety razor, the two side portions of anopen-end blade and the shaving edges thereof are sometimes deflected outof their normal relations. While the two sharpened longitudinal edgesmay be disposed accurately in parallel relation when the blade isinitially formed, it sometimes happens that when the blade is flexed thetwo edges are found to diverge toward the open end of the blade. This ispartly due to the fact that the transverse hinge portion at the solidend of the blade has a restraining effect on the two side portions whichis entirely absent at the open end of the blade. This difference instructure and behavior and possibly other reasons result at times in adeparture from parallelism of the two sharpened cutting edges of theblade. Such variation detracts from the precision of the assembledrazor, producing variations in the degree of edge exposure of the bladeand may even result in a dangerous degree of edge exposure.

I have discovered that the structure and performance of open-end bladesmay be improved by initially compensating for the possible divergence ofthe blade edges occurring when the blade is transversely flexed. I havefurther discovered that this may be done by permanently deflecting thehinge portion at one end of the blade through a small angle from theplane of the blade. By thus shaping the blade and preferably by causingthe deflected hinge portion to be demarked or set off from the body ofthe blade by lines inclined to the axis of the blade, I impart to theblade a pronounced tendency in its side portions to approach each otheror converge at the open end of the blade when the however, even if thehinge portion is annealed to som extent.

The line of deflection of the hinge, or rather the deflected area of thehinge, is determined by lines converging inwardly toward the major axisof the blade. For example, these lines of demarcation may make an angleof to to the major axis of the blade and within reasonable limits themore these lines of demarcation depart from a position the morepronounced is the effect of the deflected hinge portion when the bladeis flexed.

The hinge portion has been described as being permanently deflected fromthe plane of the blade through a small angle and by this is meant anangle in the order of 3 to 6. Such an angle is hardly detectable in theblade. It temporarily disappears when the blade is subjected to normalpressure in a stack of blades and does not in any way interfere withmechanically handling the blades or discharging them from a blademagazine.

.Another advantage incident to the blade of my invention is that itprovides the user with a convenient expedient for securing either anormal shave or a close shave with a fully clamped razor. Ordinarily theblade will be presented to the razor with its hinge deflected in thesame sense in which the blade is to be transversely flexed, that is tosay, if the blade is to be flexed to present an upwardly convex face,the blade will be presented so that the hinge portion is deflecteddownwardly, and under these circumstances the side portions of the bladewill tend to converge or approach each other as already explained. Onthe other hand by presenting the blade with its hinge deflected in anopposite sense from that in which the blade is to be deflected the stepof deflecting the blade will cause the side portions thereof to divergeor separate, and this, of course, will increase the edge exposure of theblade edge and give the user a close shave.

These and other features of the invention will be Fig. 1 is a plan viewof the blade on an enlarged scale;

Fig. 2 is a view in side elevation;

Fig. 3 is a view in perspective showing the blade as flexed upon theguard member of a safety razor: and

Fig. 4 is a similar view showing the blade in inverted position ascompared to Fig. 3.

The invention as herein shown is embodied in a blade of the Well-knownGillette type but it is not by any means restricted in its applicationto that or to any particular type of blade but, with suitablemodifications, may be embodied in any thin, flexible, open-end blade.

The blade herein shown is generallyrectangular in outline, havingreentrant corner recesses an opposite sense from that in which flexingof the blade upon the guard member is to take place.

Under these conditions it will be found that when the blade is flexed atendency is imparted to its side portions to diverge or to separate atthe open end of the blade. This tendency, kept within bounds, isusefulin providing the user with means for securing a close shave as a resultof increased edge exposure but alwayswith the blade securely clamped inthe razor. Heretofore, the only convenient way of securing an edgeexposure greater than normal has been to release the clamping pressureon the blade, and while this is effective for the desired purpose, itnecessitates the risk of shaving with a razor in which the head is.notreliably clamped and maintained in definite angularrelation.

The slot l3 terminates at its inner end in a curved enlargement I 4which defines the inner boundary of the hinge portion I 2. The hingeportion is set off from the body of the blade by two outwardly diverginglines 15 which run from the end of the enlargement [4 to the reentrantrecesses at that end of the blade. The deflection of the hinge l2 on thelines [5' is in the order of 3 to 6 and, as already stated, it isimportant to maintain the tempered resiliency of the deflected hinge.

In Fig. 3 is shown the guard or blade-supporting member 20 of a safetyrazor having an upwardly convex surface on which the blade is supportedand over which it is transversely flexed as it would be when clamped inthe complete razor. This figure also shows in dotted lines ablade-locating rib l8 which is ordinarily a part of the cap member ofthe razor and which serves to locate the blade accurately in shavingposition. When the blade of my invention" is flexed as suggested I inFig. 3, the side portions I0 and II tend .to converge on approach eachother at the open end of the blade. Thi converging tendency may bearrested by the rib l8 which thus acts as a positive stop and may beshapedso as to arrest the side portions of the blade in gauged relationin which their sharpened edges lie exactly parallel. It Will beunderstood that the converging tendency thus imparted to the sideportions Ill and II of the blade completely compensates for any tendencyof the side portions of the blade to spread from any cause whatever, andinsures the user of an accurate shaving instrument having a uniformdegree of edge exposure throughout its entire length.

In Fig. 4-the blade is shown in a reverse position upon the guard member20, that is to say, the hinge portion I2 isdeflected upwardly and in Theblade of my invention may be produced on process of manufacture bytheadditional step of engaging the hinge portion of the finished bladebetween heated plates and imparting the desired deflection to the heatedportion. This step may be carried out rapidly and conveniently withoutimpairing the temper andresiliency of the hinge portion to anyunsuitable degree.

Having thus disclosed my invention and described in detail oneillustrative embodiment thereof, I claim as new and desire to secure byLetters Patent:

1. An open-end'blade for safety razors, having side portions and. asolid, flexible transverse hinge at one end, the side portions beingspaced apart at the other end of the blade and having sharpened outeredges, the outer end of said solid hinge being permanently deflectedfrom the plane of the blade through a small angle.

2. An open-end flexible blade for safety razors, having a solid hingeportion at one end permanently deflected from the plane-of the bladethrough a small angle, and spaced side portions projecting from thehinge portion with parallel sharpened edges and tending to converge ordiverge at their outer ends when the blade as a whole is flexedtransversely.

3. An open-end flexible blade for safety razors, having spacedside-portions, a solid flexible hinge set off from the side portionsbylines-inclined to the axis of the blade and permanentlydefiected fromthe plane of the blade through a small angle. 4. lAn open-end blade forsafety razors, having a thin, flexible body divided into similar. sideportions-by a medial slot; and a transversehinge at one end'of the bladedefinedby lines'converging inwardly, andperrnanently deflected'throughan angle'of less than 6 to-the plane of the blade.

5. An open-end blade forsafetyrazors, having a thin flexible bodygenerallyrectangular-inoutline, and elongatedunsharpened"endportions-clefined by reentrant corner recesses, the bodyof the blade being" divided by a medial slot into two similaredge-bearing side portions, and apermanently deflected hinge portionconnecting the side portions-at one end of the blade;- and being cornerrecesses tothesaid medial slot.

Y JOSEPH MURO'S. Y

